Oxalyl chloride → 2,3-Dichloro-4-methanesulfonylbenzoic acid 4-oxobicyclo[3.2.1]oct-2-en-2-yl ester

HRID 720759Notes

Reaction equation

HRID 720759 reaction equation
C[O-].[Na+].[CH2:4]=[C:5]1[CH:11]2[CH2:12][CH:8]([CH2:9][CH2:10]2)[C:7](=[O:13])[O:6]1.[Cl:14][C:15]1[C:23]([Cl:24])=[C:22]([S:25]([CH3:28])(=[O:27])=[O:26])[CH:21]=[CH:20][C:16]=1[C:17](Cl)=[O:18].C(Cl)(=O)C(Cl)=O>C1(C)C=CC=CC=1.CN(C)C=O.C1(C)C=CC=CC=1.C(#N)C.CO>[O:13]=[C:7]1[CH:8]2[CH2:12][CH:11]([CH2:10][CH2:9]2)[C:5]([O:6][C:17](=[O:18])[C:16]2[CH:20]=[CH:21][C:22]([S:25]([CH3:28])(=[O:27])=[O:26])=[C:23]([Cl:24])[C:15]=2[Cl:14])=[CH:4]1

Participants

9

Reactant 4

HCID 65578Oxalyl chlorideHCID 10942334Sodium MethoxideHCID 129939774-Methylene-3-oxabicyclo[3.2.1]octan-2-oneHCID 152752322,3-Dichloro-4-methanesulfonylbenzoyl chloride

Product 1

HCID 207592342,3-Dichloro-4-methanesulfonylbenzoic acid 4-oxobicyclo[3.2.1]oct-2-en-2-yl ester

Reagents, catalysts & solvents 4

HCID 887MethanolSolventHCID 1140TolueneSolvent2×HCID 6228DimethylformamideSolventHCID 21584213Acetonitrile tolueneSolvent

Conditions

Temperature
20 °C

Procedure

3.6 g of a 30% sodium methanolate solution (0.022 mol) are heated to a column head temperature of 108° C. in a mixture of 19 ml of toluene and 1 ml of dimethylformamide, methanol being removed by distillation. With removal of methanol by distillation being continued, 2.76 g (0.02 mol) of 4-methylene-3-oxabicyclo[3.2.1]octan-2-one dissolved in 3 ml of toluene are then added dropwise. After stirring for one hour, the mixture is cooled to a temperature of 20° C. and, while controlling the temperature, a solution in 1:1 toluene/acetonitrile of 6.32 g (0.022 mol) of 2,3-dichloro-4-methanesulfonylbenzoyl chloride freshly prepared with oxalyl chloride is introduced. After stirring briefly, extraction is carried out with a small amount of ethyl acetate against a slightly alkaline-aqueous solution at pH 10. 2,3-Dichloro-4-methanesulfonylbenzoic acid 4-oxobicyclo[3.2.1]oct-2-en-2-yl ester is obtained in the form of an amorphous crystallisate in a yield of 5.5 g (71%). 1H-NMR (DMSO-D6): 8.19 ppm, 2H, 5.85 ppm, s, 1H, 3.48 ppm, s, 3H, 3.07 ppm, m, 1H, 2.84 ppm, m, 1H, 1.9–2.2 ppm, 4H, 1.7 ppm, 2H.

Workup

  1. customremoved by distillation
  2. customWith removal of methanol
  3. distillationby distillation
  4. additionare then added dropwise
  5. additionis introduced
  6. stirringAfter stirring briefly
  7. extractionextraction

Sources & evidence

ORD record
ord-e0fb700b77234ccaafe4832098d5913c
Source dataset
uspto-grants-2006_11
Patent number
US07135574B2

Reaction notes

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